The point is they clearly perfected their techniques over time. We have evidence of failures and mistakes too. There is nothing about the ancient pyramids that

The point is they clearly perfected their techniques over time. We have evidence of failures and mistakes too. There is nothing about the ancient pyramids that lies beyond human capability. There are plenty of videos on youtube of 1-4 people moving 15-ton stone blocks around. Occam's razor: the simplest explanation is humans built the pyramids and no aliens were involved.